Kepeater-netwobk-selectiito apparatus



J. F. TOOMEY AND C. F. DEMAREST.

BEPEATER NETWORK SELECTING APPARATUS.

' APPLICATION HLEb JULY 9,1919.

Camasdegfeg g Patented June 7, 1921.-

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IN V EN TORS @LJTflBl/M/ yj x, A TTORNEY JIM/4e J. F. TOOMEY AND 0. F. DEMAREST.

REPEATER NETWORK SELECTING APPARATUS.

APPLJCA iON FILED JULY 9.1919.

1,380,75 1 Patented June 7, 1921.

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m T INVE/VTORS A TTORNEY from the line circuit, the repeater wouldnot UNiTsn stares PATENT oF IcE.

JOHN r. rooivrnY, or new Yon-K, Ann cnaarns s. :onraennsr, or BROOKLYN, NEW

YORK, ASSIGNORS r0 Annnrcan rnrrirnonn. AND TELEGRAPH COMPANY, A con- PORATION 01 NEW YORK;

REPEATER-NETWORK-SELECTING APPARATUS.

rssoyrer T 0 aZZ whom it may concern Be it known that we, JOHN F. TooMnY and CHAnLns S. Dmmnns'r, residing at New York and Brooklyn, in the counties of New York and Kings, respectively, and State of New York. have invented certain Improve ments in Repeater-Network-Selecting h paratus, of which thetollowing is a speci fication.

This invention relates to telephone rcpeaters and more particularlyto the arrangements for controlling the selection of the requisite electrical networks for balancing the transmission lines that may be connected with the repeater.

In order that a telephonerepeater may operate properly, it is necessary to provide an electrical network or a group of such networks to balance the line and such auxiliary apparatus that may be connected therewith. It is customary in long distance telephony to use the ph sical circuits not only for purposes of telephony, but also to provide telegraph circuits; and, moreover, groups oi 3h sical circuits are freouentl combined in order to provide phantom telephone circuits.

in order that these physical circuits may perform these various functions, 1t is necessary to connect. with the physical circuits various types of auxiliary apparatus such as composite sets, composite ringers and phantom coils. W hen such'circuits have a telephone repeater connected to them it is necessary in order that the repeater may function properly to connect into the repeater circuit a group of electrical networks, each of which has the same impedance characteristic as a part or the transmission circuit which the entire group of networks is intended to balance.

When a telephone repeater, having associated with. it a group of networks, as described above, is connected to a line having corresponding auxiliary apparatus, a bal-' anced condition exists and the repeater will operate properly. If, however, the auxiliary apparatus, or some part thereof, as for example the composite apparatus, which adapts the physical circuit for combined-telephone and telegraph purposes, should be removed Specification of Letters Patent. Patented June 7 1921 Application filed July 9, 1919. Serial No. 309,595.

be properly, balanced unless composite everthe corresponding; auxiliary apparatus 1 is removed from the line. Furtherobjects of this invention will be apparent from the following description when read in connection with the accompanying drawing, the iigures ofwhich when Fig. 2 is placed in uxtaposition to the right of Fig l constitute a circuit diagram of one embodiment of the invention. a y

In the drawing L vnd L represent two physical circuits extending in one direction from a repeater station and having superimposed thereon phantom circuit L L and L represent two other physical circuits eX- tending in another direction from the said repeater station having superimposedthereon a phantom circuit L The circuits L L and L5 are connected with thecireuits 11 ,11 and L respectively, by means of the repeaters R R and R respectively. As-

sociated with each of the lines L L L and' Repeater R which connects lines L and L comprises two repeater elements A, andv A and a group of i'ictwor cs on Xll, and LN, adapted to balance line L, and its auxiliary apparatus, and networks Cli and LN, adapted to balance line-ll and its Networks LN, and;

auxiliary apparatus. LN have the same impedance characteristics as the lines L and L respectively. Net works XN, and XN have the same characteristics as the composite sets X andX respectlvely, and the networksCll and (3N have the same, characteristics as the phantom coils C and C respectively.

The repeaterlt is slmllflflll arrangement to the repeater R and the networks asso ciated therewith are adapted to balance the lines L and L and associated apparatus. Repeater R which is adapted to connect the phantom line L, with the phantom line L is similar in arrangement with repeaters R and B The networks LN and LN associated with repeater R are adapted to balance the phantom circuits L and L respectively, the networks XN and XN and the networks CN and ON are adapted to balance the repeater circuit R against the effect of the composite sets and the phantom coils in the side circuits oft-the phantom circuits L and L respectively.

This invention will be more fully understood from a description of its mode of operation. It all of the auxiliary apparatus is connected with the lines as shown in the drawing, all of the networks shown will be effectively connected with the repeater cir cuits, so as to balance the lines and their associated apparatus. If, however, it becomes necessary to disconnect the composite set X from the line L on account of injury to the composite set, or for any other reason, the plug P is inserted in the jack J and plug P inserted in jack J thereby establishing a circuit from battery 13,, relays S and S conductor-1, contacts of plugs P and P and jacks J 1 and J respectively, in parallel, upper normal contact of jack J to ground. Relays S and S, are thereby operated, disconnecting the network XN, from the group of networks adapted to balance the line L and its associated apparatus. The remaining networks LN and CN will balance the line L, and the phantom coil C and therefore the repeater circuit remains balanced.

VJ hen the composite apparatus is removed from one or" the side circuits of a phantom circuit, it is customary in order to maintain balanced conditions to remove the corresponding composite apparatus from the other side circuit. Accordingly plugs P and P would be inserted in acks J and J 4 respectively, thereby effectively removing the composite set X, from the line L and establishing a circuit from battery B relays S ands conductor 2, contacts of plugs P P and jacks J 5,, respectively, in parallel, and the upper normal contact of jack J to ground. Relays S and S, are thereby operated, thus disconnecting composite network XN from the group of networks with which it is associated. Line L and its phantom coil C are therefore balanced by networks LN and CN so that the repeater will operate properly.

Vhen the composite sets are removed from the sidecircuits of the phantom, it is, of course, necessary that the network associated with the phantom repeater and which is adapted to balance the effect of the composite sets upon the phantom circuit should be removed from the phantom balancing networks. "When relaysS and S are operated as the result of the removal of the composite sets X and X contacts 3 and 4;, respectively, were closed, thereby establishing a circuit from battery 3,, relays S and S conductors 5 and 6 in parallel to ground. As a result of the operation of relays S and S the composite balancing network XN is removed from its associated networks and the remaining networks LN and 6N are adapted to balance the phantom circuit when the composite sets X and X have been disconnected.

In a similar manner the networks XN XN and XN may be disconnected from their respective repeater circuits whenever composite sets X and X are disconnected. The phantom balancing networks 0N 2, CNS and CN 3T6 ShOWIl permanently connected in the balancing circuit since, in practice, the phantom coils are seldom disconnected from the line. And, furthermore, this principle and the means for applying it are applicable to any type of auxiliary apparatus and its corresponding network.

if a composite set, as for example X which is ordinarily associated with line L has become detective so as to necessitate its removal from the line and it is desired to maintain telegraphic service, the-plug of a portable composite set may be inserted in the jack J and a corresponding plug at the other end of the said portable composite set in the jack J By the insertion of the plug of the portable composite set in the jack J the ground is removed from the circuit of the relays S and S, by the opening of the upper normal contact of ack J As a result relays S and S, are prevented from operating when the set X, has been replaced and the network XN, remains in the repeater balancing circuit in order to balance the portable composite set that has been temporarily connected with the line L in place of composite set X Furthermore, relays S and S, are not operated, so that the composite balancing network XN associated with the phantom repeater likewise remains connected with its said repeater circuit.

It will be seen, therefore, that this invention provides smiple means for disconnecting a balancing network from a telephone repeater circuit whenever its corresponding auxiliary apparatus is disconnected from the line circuit. As a result, only such networks will be connected as are necessary to balance the line and such auxiliary apparatus as may be connected with said line, so that repeater will always be in a balanced condition and, therefore, will operate properly.

Although this invention has been shown as embodied in a particular form, it is un- 1 derstood that it is capable of embodiment in other and difierent forms without dee parting from the scope of the following claims.

What is claimed is:

1. In a telephone transmission system, the combination of a transn'iission line, auxiliary apparatus associated withsaid line, a telephone repeater permanently connected with said line, a group of individual balancing networks adapted to balance said line and said auxiliary apparatus, and normally effectively connected with said repeater circuit, switching relays associated with said auxiliary balancing networks adapted to be energized by the disconnection of the auxiliary apparatus, and means to prevent the energization of the said relays when similar apparatus has been connected with the said line to replace the apparatus effectively disconnected trom the said line.

2. in a telephone transmission system, the

' combination of two transmission circuits, a

repeater circuit for operatively connecting together said transmisslon circuits, auxiliary apparatus associated with each of said 7 transmission circuits, networks associated with said repeater to balance each of said transmission circuits, auxiliary networks associated with said repeater to balance said auxiliary apparatus, switching means associated with said auxiliary networks adapted to be energized by the disconnection of its corresponding auxiliary apparatus, and means to prevent the energization of the said relays when similar apparatus has been connected with the said line to replace the apparatus effectively disconnected from the said line.

3. In a telephone transmission systemthe combination of a phantom group comprising two physical circuits and a phantom circuit, auxiliary apparatus associated with said physical circuits, a telephone repeater connected with each of said circuits, net works associated with each repeater to balance the circuits associated therewith, aux iliary networks associated with each repeater to balance the auxiliary apparatus of the circuits associated therewith, and switching means adapted to be energized by the disconnection of said auxiliary apparatus, whereby a balancing network corresponding to said auxiliary apparatus may be eitectively disconnected from the said repeater whenever the auxiliary apparatus is disconnected from the line circuit.

4. In a telephone transmission system, the combination of a phantom group comprising two physical circuits and a phantom circuit extending in one direction, a corresponding group extending in another direction, a group of telephone repeaters adapted to connect the corresponding physical and phantom circuits of each of said phantom groups, auxiliary apparatus associated with said physical circuits, networks associated with each repeater to balance the circuits connected thereto, auxiliary networks associated with each repeater to balance the auxiliary apparatus of the lines connected thereto, and switching means associated with the auxiliary networks whereby the said aux iliary networks of a physical circuit and of a phantom circuit may be disconnected from the said repeater whenever the corresponding auxiliary apparatus is disconnected from a physical circuit.

5. In combination with a transmission line, an auxiliary apparatus associated therewith, a balancing arrangement therefor comprising an artificial line simulating the transmission line, an auxiliary balancing set for simulating the auxiliary appara tus, switching means designed to render the auxiliary balancing set inoperative at will and means to prevent the 'renderlng of the said balancing set inoperative whenever the apparatus is replaced by similar apparatus.

In testimony whereof we have signed our names to this specification this 8th day of July, 1919.

JOHN F. TOOMEY. CHARLES S. DEMAREST. 

